In the field of well logging, there are several well-known methods for displacing measuring instruments in greatly inclined or even horizontal pipes. It is possible to use drill rods made up end to end and equipped with a transmission cable placed in the inner space thereof, a continuous steel tubing (cabled coiled tubing) also comprising a transmission cable, or mechanical means for displacing measuring tools, such as hydraulically, electrically or electro-hydraulically-powered tractors. Measuring probe tractors are generally fed by an electric cable which supplies electric power to an electric motor driving a high-pressure hydraulic pump. The high-pressure hydraulic fluid actuates wheels placed against the wall of the well or of the pipe. The tensile or thrust force is of the order of 5 to 10 kN. These tractors are mechanically complex and costly because they cannot be too heavy, but they must however withstand the high pressures and temperatures to which they can be subjected in the pipe. Furthermore, the tensile strength of the electric feeder cable does not allow an excessive weight of the tractor. The power supply that can be transmitted is also limited. Moreover, the tensile or the thrust capacity depends on the coefficient of friction between the driving wheels and the wall of the pipe. This explains notably the relatively limited thrust or tensile capacities considering the weight of the feeder cable, the weight of the tractor itself and the weight of the tools to be displaced by the tractor. A conventional logging cable has a steel armouring with a rather high linear weight and wall friction coefficient. When a certain cable length is horizontal, the force of the tractor may not be sufficient to displace the total load. Furthermore, tractors cannot work in open holes because the rugosity of the rock face does not allow correct and effective contact of the driving wheels. Using a continuous coiled tubing equipped with an inner logging cable does not eliminate these drawbacks, on the contrary, because the linear weight thereof is even greater. Furthermore, the surface installation for maneuvering a coiled tubing is bulky and very costly.